Arc lamp

ABSTRACT

The disclosure embraces an arc lamp construction utilizing a lamp comprising a gas-filled envelope containing spaced electrodes in combination with magnetic forces for controlling the arc flame, and a mounting for the gas-filled lamp adjustable to control the relative position of the arc with respect to a reflector.

United States Patent Inventor Harold M. Plumadore Toledo, Ohio AppL No.792,387 Filed Jan. 21, 1969 Patented Nov. 30, 1971 Assignee The StrongElectric Corporation Toledo, Ohio ARC LAMP 7 Claims, 11 Drawing Figs.

U.S. Cl 240/44.2, 240/41 A Int. Cl F2lv 19/02 Field of Search 240/442,

[56] References Cited UNlTED STATES PATENTS 2,757,277 7/1956 Pennow240/41 2,767,343 10/1956 Yaeger 313/161 3,168,986 2/1965 Jeffree et al.240/442 Primary Examiner-Samuel S. Matthews Assistant Examiner-RichardL. Moses Attorney-Harry O. Ernsbcrger ABSTRACT: The disclosure embracesan arc lamp construction utilizing a lamp comprising a gas-filledenvelope containing spaced electrodes in combination with magneticforces for controlling the arc flame, and amounting for the gas-filledlamp adjustable to control the relative position of the are with respectto a reflector PATENTEU NUV30 I971 SHEET 1 BF 4 INVENTOR. wwm Mflu/lmwmf PATENTEU W30 ism SHEET 2 [IF 4 INVIL'NTUR. #414 040 MPlum/00a;

,47 TOP/VfV PATENTEDuuvaomn 3,624,386

SHEET 3 [IF 4 INVENTOR. HAWflAfi M PAM/400M ARC LAMP Arc lamps of thetype wherein an arc is established by current flow through spaced carbonelectrodes have been used extensively for cinematography, televisioncasting and illumination for theatrical purposes. In such lamps theelectrodes at the region of the arc are unconfined and the light raysfrom the incandescent ionized gases at the arc are projected from areflector to a desired area. In lamps of this character the electrodesare consumed comparatively rapidly requiring frequent replacement. Theconstant consumption of the electrodes results in deposition of oxideparticles upon the reflector requiring frequent cleaning of thereflector in order to main -tain efficient light projection.

Endeavors have been made to utilize a lamp of a character whereinelectrodes are confined in a transparent envelop filled with an inertgas, such as xenon, the electrodes being spaced to provide an arc sourceof light. Heretofore, if the xenon lamp were mounted with the elongatedlamp body in a horizontal position, the incandescent gases or are flametend to be offset vertically upwardly from the axis of the electrodes.Therefore present practice is to mount the lamp with the axis of theelectrodes in a vertical position. Operation of the lamp in a verticalposition rendered it impossible to use an efficient form of opticalsystem in a light projector. Such lamp used in other than a verticalposition effected an overconcentration of heat at an adjacent region ofthe transparent envelop, such as an envelope of quartz, resulting indamage to the envelope.

The present invention embraces an arc lamp construction utilizing agas-filled electrode illuminating means for producing an arc wherein thelongitudinal axis of the lamp construction is disposed in asubstantially horizontal position in association with means forconfining the incandescent gases of the arc flame substantially at theregion between the adjacent extremities of the electrodes whereby a highefficiency of illumination from the arc is attained.

An object of the invention resides in an arc lamp arrangement utilizingan elongated lamp construction wherein electrodes are disposed in asealed transparent envelope filled with an inert gas, such as xenon, incombination with magnetic means disposed with respect to the arc betweenthe electrodes to stabilize and maintain the arc flame centralized inthe region between the electrodes thereby eliminating concentration ofheat from the are at any localized region of the confining envelope.

Another object of the invention resides in a mounting means for anelongated type of gas-filled electrode arc lamp in a light utilizationapparatus, the mounting means providing for universal adjustment of thelamp facilitating the accurate positioning of the are at the focal pointof a reflector of the apparatus.

Another object of the invention is the provision of an arc lampconstruction embodying an arc source of light provided by current flowbetween electrodes sealed in a gas-filled envelope wherein one endregion of the elongated lamp is pivotally supported and the other endregion rendered ad justable in vertical and transverse directions foraccurately positioning the region of the are at a focal point of thereflector, the arrangement including the establishment of magneticforces acting in a direction to confine the flame of the arc to acentralized region at the adjacent extremities of the electrodes.

Another object of the invention resides in an arc lamp constructionwherein an elongated xenon lamp is disposed substantially horizontallyin a lamp housing, and means for circulating air through the housing toconvey away heat developed by the arc and to cool the current conductorsat the ends of the xenon lamp.

Further objects and advantages are within the scope of this inventionsuch as relate to the arrangement, operation and functions of therelated elements of the structure, to various details of constructionand to combinations of parts, elements per se, and to economies ofmanufacture and numerous other features as will be apparent from aconsideration of the specification and drawing of a form of theinvention, which may be preferred, in which:

FIG. I is a side elevational view of an arc lamp light projectingstructure embodying a form of the invention;

FIG. 2 is a top plan view of the arc lamp structure shown in FIG. 1;

FIG. 3 is a vertical longitudinal sectional view taken substantially onthe line 3-3 of FIG. 2;

FIG. 4 is a longitudinal horizontal sectional view with the xenon lampremoved, the view being taken substantially on the line 4-4 of FIG. 3;

FIG. 5 is an enlarged fragmentary detail view taken substantially on theline 5-5 ofFlG. 3;

FIG. 6 is an elevational view taken substantially on the line 6-6 ofFIG. 3 illustrating one position of an arc flame control means;

FIG. 7 is a fragmentary sectional view taken substantially on the line77 of FIG. 6;

FIG. 8 is a fragmentary view of a portion of the gas-filled lampillustrating the relative position of the arc flame stabil ized betweenthe electrodes;

FIG. 9 is a view illustrating a modified position for the arc flamecontrol means;

FIG. 10 is a view illustrating a form of electromagnetic means forcontrolling the arc flame, and

FIG. 11 is a view similar to FIG. 9 illustrating a modified position forelectromagnetic means for controlling the arc flame.

While the invention is illustrated in a projection arc lamp especiallyadapted for cinematography, television casting and theatrical lighting,it is to be understood that the invention may be used with other formsof lamp construction such as searchlights and the like.

FIGS. 1 through 4 illustrate a projection lamp construction embodying aform of the invention. The projection lamp construction is inclusive ofahousing 10 of substantially rectangular shape elongated in the directionof light rays projected from a reflector. The lamp structure has a baseconstruction 12, preferably of cast metal, which supports an upperportion or section 14 of the housing fashioned of sheet metal. The sheetmetal portion 14 of the housing is fashioned at one side with an openingnormally closed by a movable door 16, the door being pivotally supportedby pivot pins mounted in lugs or bosses 18 provided on the upper portionof the housing.

The upper portion of the housing 10 is equipped with a baf fle or member20, particularly shown in FIG. 3, secured to the roof 21 of the housingby means of brackets 22. The baffle 20 is fashioned with a vent stack 24through which air is vented from the housing 10 to convey away the heatfrom the arc lamp. Mounted upon a raised portion 26 adjacent the rearportion of the base 12 is a pedestal or support means 28 hav ingforwardly extending projections 30 to which is secured a reflectormounting means or supplemental frame 32 particularly shown in FIG. 3.

Supported upon the mounting means 32 is a reflector 35 preferably ofellipsoidal shape adapted to reflect or project rays of light from thearc forwardly through an opening in the front of the housing 10. Thereflector mounting frame 32 is equipped with peripherally spaced springclips 36 which engage the rear surface of the reflector 35. Thereflector is held in engagement with the spring clips 36 by a latchmember 37 pivotally supported on a lug 38, the latter carried by thereflector supporting frame 32. The latch member 37 is illustrated inFIG. 3 in reflector retaining position and is adapted for pivotalmovement to facilitate removing the reflector.

Light rays from the reflector 35 are projected through an opening 40 inthe housing section 14 and through an opening 41 in a supplementalhousing 42 secured on the front panel of the housing 10. A douser screenor light impeding member 43 is secured to a shaft 44 journaled in bosses45 carried by the supplemental housing 42.

The shaft 44 extends exteriorly of the douser or supplemental housing 42and is equipped with a handle 46. The douser or light impeding member 43is shown in open position in FIG. 3 and is manually movable about theaxis of the shaft 44 for closing the opening 41 to interrupt theprojection oflight.

The lamp 48 providing the arc source of light is of elongatedconstruction and includes enlarged end terminal regions 50 and -2, theend construction 50 supporting a cathode electrode 54. the enlargedportion 52 supporting an anode electrode 56, the tips or extremities ofthe electrodes being spaced apart as shown in FIG. 3 to provide a gap 57in which the arc is formed by electric current flow between theelectrodes. A current conductor 58 sealed in the end region 50 isconnected with the electrode 54 and with an igniter 59 of conventionalconstruction for initiating operation of the lamp, the igniter beingsupported on the pedestal 28. A power switch 61 controls current supplyto the electrodes, and an igniter switch 65 is provided for energizingthe igniter 59 for striking the are between the electrodes.

Conductor 60 is sealed in the end region 52, and is connected with theelectrode 56 and with a power supply. The current supply is preferablyAC current rectified to direct current with a minimum current ripple.The lamp is fashioned with an elongated transparent envelope 62fashioned of quartz of good optical quality, the envelope having anintermediate spherically shaped portion 64 adjacent the are which isformed between the tips of the electrodes.

The envelope 62 is filled with an inert gas under pressure, such asxenon. The focal point of the reflector 35 is at the gap 57 on thehorizontal axis of the electrodes. The lamp 48 is adjustable so that thearc may be adjusted to the most efficient light projecting position withrespect to the reflector 35 whereby maximum illumination efficiency maybe attained.

Referring particularly to FIGS. 3 and 4, the base structure 12 isfashioned with boss portions 66 and 67. Each of the bosses is bored toprovide a journal support for a rotatable shaft 69. Rotatably mounted onthe front sidewall of the base 12 is a knurled knob 70 which isconnected with one end of the shaft 69 by a flexible cable 72 ofconventional construction of a character for transmitting rotation ofthe knob 70 to the shaft 69. A pedestal or member 74 provides a supportfor one end region of the xenon lamp construction 48.

The pedestal 74 is fashioned with a boss 76 which is bored toaccommodate the shaft 69, the pedestal 74 being slidable along theshaft. The pedestal 74 is fashioned with a second boss 78 having athread bore accommodating a threaded portion 79 of the shaft 69 which isthreaded into the threaded bore in the boss 78. Through thisarrangement, rotation of the knob 70 effects rotation of the shaft 69through the flexible cable 72 for adjusting the lamp supporting pedestalor member 74 lengthwise of the housing 14. the direction of adjustmentbeing dependent upon the direction of rotation of the central knob ormember 70.

The member 74 is fashioned with a bifurcated projection 81 whichstraddles a pin 82 threaded into a bore in a projection 83 integrallyformed on the base member 12. The pin 82 is locked to the projection 83by a locknut 84. The pin 82 extending between the furcations of thebifurcated portion 81 is ofa diameter to facilitate sliding movement ofthe member 74 relative to the pin 82. The pin 82 serves to maintain themember 74 for adjustment in a rectilinear direction lengthwise of thehousing without pivotal movement of the member 74.

The pedestal or member 74 is fashioned with an upwardly extending webportion 86 which, as shown in FIG. 5, is fashioned at its upper end withan opening 88 having chamfered entrance regions 90. A lamp mountingbracket 92 has a bifurcated portion, the furcations 94 straddling theupper portion of the web 86. The furcations 94 are respectivelyfashioned with a smooth bore and a threaded bore to accommodate a bolt96 which extends through the opening 88 in the web 86 to mount thebracket 92 on the web 86 of member 74.

The web portion between the furcations 94 is ofa thickness or dimensionto accommodate limited relative swivel move ment of the bracket 92 withrespect to the web 86 to facilitate adjusting movement of the other endregion of the lamp. The lamp support bracket 92 has a semicylindricalrecess or cradle 98 which receives an elongated cylindrical portion 63of the xenon lamp envelope 62.

The portion 63 is embraced by a clamp member 100 which may be drawn intosnug engagement with the lamp portion 63 by screws 101. Through thisarrangement. the lamp may be adjusted lengthwise along the axis of thereflector 35.

Means is provided engageable with the other end region of the xenon lamp48 for adjusting the said end region vertically and transversely of theaxis of the reflector to secure accurate positioning of the arc in thespace 57 with respect to the light projecting surface of the reflector35, this arrangement being shown particularly in FIGS. 3 and 44 Thepedestal or member 28 at the rear of the reflector is fashioned with aboss 104 and a second boss 106 spaced transversely from the first bossas shown in FIG. 4. The boss 104 is bored to journally support a shaft108. The boss 106 is provided with a threaded bore to receive a threadedtenon 109 of the shaft 108. Journally supported upon means carried bythe base structure 12 at the front side thereof is a rotatable knob ormember 110. A flexible cable 112 has one end secured to the rotatableknob and the other end secured to an end of the shaft 108.

A movable carriage 114 is mounted upon the shaft 108. The carriage 114is fashioned with a first projection or boss portion 116 having a boretherein receiving the shaft 108, the bore being slightly larger than thediameter of the shaft to accommodate slidable movement of the carriagealong the shaft.

The carriage 114 is fashioned with a second projection or boss portion118 provided with a threaded bore accommodating the threaded tenon 109on the shaft 108. The carriage 114 is equipped with a member or block120 having a generally V- shaped notch 122 for receiving and supportingan end region of the xenon lamp construction 48.

As shown in FIG. 3, the enlarged region 50 of the lamp con struction isnested or cradled in the V-shaped notch 122 provided in the block ormember 120. A rotatable control knob 126 is journaled by means supportedby the base structure 12. The pedestal 28 is fashioned with ahorizontally extending projection 128 having a vertically arrangedthreaded bore accommodating a threaded stub shaft 130. The movablecarriage 114 is fashioned with a horizontal pad or projection 132 whichis engaged by the upper end of the threaded stub shaft 130, as shown inFIG. 3.

One end of a flexible cable 134 is connected with the control knob 126and the other end of the cable 134 fixedly secured to the lower end ofthe threaded stub shaft 130. As will be apparent from FIG. 3. rotationof the stub shaft 130. having threaded connection with the projectionI28, elevates or lowers the end region of the lamp construction 48depend ing upon the direction of rotation ofthe stub shaft 130.

Rotation of the control knob 110 is transmitted by the flexible cable112 to rotate the shaft 108. rotation of the shaft 108 moving oradjusting the carrier 114 in a transverse direction depending upon thedirection of rotation of the knob 110.

As the end region 50 of the xenon lamp 48 is nested in the notch orcradle 122 of member or block 120, this end region of the lamp 48 willbe moved transversely causing slight pivotal movement of the lampconstruction 48 about a vertical axis through the opening 88 in the web86 accommodating the screw 96 so that the tips of the electrodes 54 and56 are adjusted transversely of the longitudinal axis of the reflector35 to effect transverse adjustment of the arc.

Manual rotation of the control knob 126 is transmitted through theflexible cable 134 to the vertically disposed threaded stub shaft 130.As the upper end of the stub shaft engages the pad 132 on the carriage114. the adjustment end region 50 of the lamp construction 48 will beelevated or lowered depending upon the direction of rotation of the knob126 and the stub shaft 130. Through this arrangement the lampconstruction 48 is pivotally moved in a vertical plane about thehorizontal axis of the screw 96 whereby the tips of the electrodes 54and 56 may be adjusted vertically whereby the position of the arc may bevertically adjusted with respect to the axis of the light-reflectingsurface of the reflector 35 Heretofore it has not been practicable toutilize a xenon lamp in a substantially horizontal position for severalreasons. The body of incandescent ionized gases of the arc is normallydistorted upwardly by the intense head in the region of the arc causinga concentration of heat at a localized region of the quartz envelopabove the arc.

This thermal instability sets up or establishes severe stresses in thequartz envelope which weaken the lamp structure and as comparativelyhigh pressure exists within the quartz envelop, the envelope is liableto be fractured by the effects of the localized heating and internalpressures.

Due to the vertical distortion of the body of incandescent ionized gasesproviding the light source, the light transmitted to the reflector doesnot emanate from a comparatively small focal area but from the largearea of the distorted body of incandescent gases between the electrodesThis condition results in very inefficient diffused reflected light andimpairs the control of light rays projected from the reflector.

In the arrangement of the invention means is provided exerting forces onthe ionized body of incandescent gases of the arc for eliminating thevertical distortion or distention of the gases and stabilizingincandescent gases in a sphere or ball-like body centrally disposedbetween the tips of the electrodes. Magnetic forces are employed forperforming this function. Referring particularly to FIGS. 3, 4, 6 and 7.one form of means for establishing magnetic forces is illustrated andincludes an L-shaped bracket 136 secured to the base portion 137 of thebase 12 by screws 138.

Secured to an upwardly extending portion 139 of the bracket 136 is amagnet support means or block 140. The upwardly extending portion 139 ofbracket 136 is fashioned with a vertical slot 142 which accommodatessecuring screws 143 extending into threaded openings in the block 140.

The block 140 is fashioned with a bore to accommodate a bar magnet 146of the permanent magnet type such as an Al nico magnet held in positionby a setscrew 141. The block is bored to position the bar magnet 146with its longitudinal axis disposed transversely of the longitudinalaxis of the lamp 48 and transversely of the housing as illustrated inFIGS. 4 and 6.

As shown in FIG. 3, the bar magnet 146 is disposed with its centralregion substantially vertically beneath the region of the arcestablished between the tips of the electrodes. In reference to theposition of the magnet in respect of polarity the south pole or negativepole end 148 is disposed at the left side of a vertical plane A-Athrough the longitudinal axis of the lamp 48 and the axis of thereflector 35 viewed from the front of the reflector as illustrated inFIG. 6.

The north pole end or positive pole 150 of the bar magnet is disposed anequal distance to the right side of the plane A-A as viewed in FIG. 6.For most efficient action of the magnetic forces on the body ofincandescent gases it is preferable the central position of the magnetbe on the plane A-A. although effective results may be attained if thebar magnet 146 is disposed a slight distance in either transversedirection from the central position illustrated in FIGS. 4 and 6.

It is found that by positioning the magnet means 146 in the positiondescribed with respect to the body of incandescent gases providing theare light, the body of incandescent gases is drawn downwardly bymagnetic forces so that the central region of the body of theincandescent gases is substantially at the axis of the electrodes andthat the body of incandescent gases becomes substantially spherical witha minimum of distortion. By stabilizing the body of incandescent gasescentrally between the electrodes, there is no concentration of heat at alocalized region of the spherical portion 64 of the quartz envelope sothat localized thermal stresses are eliminated.

The concentration of the body of incandescent gases into a smallercomparatively spherically shaped volume more nearly approaches a pointsource of light at the focal point of the reflector so that the rays oflight projected from the reflector are better controlled and may beconcentrated in a smaller area for illumination purposes. It is alsofound that by stabilizing the incandescent gases between the electrodesin a spherically shaped body that improved efficiency of light rays aredirected to the reflector with an increased intensity in the usablelight projected from the reflector. It is also found that theconcentration and stabilization of the incandescent body of gases on thecentral axis of the electrodes improves the light intensity to an extentthat the current supplied to the arc may be reduced and still provide anamount of light directed to the reflector to secure efficient projectedlight.

FIG. 8 is illustrative of the effect of the magnetic forces instabilizing the body of incandescent gases between the electrodes. Therelative position and general shape of the distorted body ofincandescent gases without the stabilizing effect of the magnetic forcesis indicated in broken lines at 152. In this position the incandescentgases are normally distorted upwardly to a position wherein the regionof the spherically shaped portion of the quartz envelope above thedistorted body of gases is subjected to a concentration of heat from thegases.

With the use of the bar magnet 146 positioned as shown in FIG. 6, thebody of incandescent gases is indicated at 154 in full lines where itwill be seen that the body of incandescent gases is more nearlyspherical in shape with its center substantially on the axis of theelectrodes and at the focal point of the reflector.

The effect of the magnetic forces provided by the magnetic means 146 maybe varied by adjusting the relative position of the bar magnet 146vertically and thereby make possible the most efficient stabilizedposition of the body of incandescent gases for efficient illuminationfrom the reflector.

The size of the bar magnet 146 and its relative position with respect tothe arc vary with the amount of current producing the arc and thestrength of the magnetic forces. As an example in utilizing an xenonlamp of 6 kilowatts, a bar magnet 146 of about 1 inch in diameter isdisposed with its axis approximate ly 7 inches below the longitudinalaxis of the lamp, the length of the magnet bar being between 4 and 5inches.

It is further found that the spacing between the tips of the electrodes54 and 56 may vary between 3 millimeters and I2 millimeters dependingupon the capacity of the lamp and the size and focal length of thereflector 35 with which the lamp is used. It has been found preferableto utilize a spacing for the electrodes to minimize the volume ofincandescent gases in the arc and yet secure efficient light projectedfrom the reflector by reducing the volume of the body of incandescentgases providing the arc.

The light source provided by the stabilized arc more nearly approaches apoint providing for better control of light rays from the reflector aswell as to promote a reduction in the amount of current for establishingthe arc. While the bar magnet illustrated has end surfaces in convergingangular planes, it is to be understood that a bar magnet having its endsurfaces in substantially parallel planes may be used if desired.

FIG. 9 illustrates a modified positioning for the bar magnet. As shownin FIG. 9, a bracket I36a is secured to the baffle member 20 or to othersupport means. The bar magnet 146a is mounted in a block 14011 which isadjustably secured to the bracket 136a by bolts 1430. The magnet 1460 isdisposed adjacent the upper terminus of the reflector with the axis ofthe bar magnet 146a in a transverse vertical plane passing through thearc established in the space 57 between the tips of the electrodes.

In this form, the bar magnet 146a is positioned whereby the north orpositive pole end is disposed at the left side of the plane AA shown inFIG. 6 viewed from the front of the reflector 35. With the bar magnet1460 in such position. the magnetic forces repel the normally upwardlydistorted body of incandescent gases, forcing them downwardly tostabilize the body of incandescent gases more nearly centrally on theaxis of the electrodes.

Such magnetic forces eliminate the distortion of the arc flame orincandescent gases and provide a more nearly spherically shaped body ofincandescent gases, thus improving the efficiency of light projectedfrom the reflector and eliminating concentration of heat in a localizedarea of the spherical portion 64 of the quartz envelope above the bodyof gases.

FIG. is a view similar to FIG. 7 illustrating an electromagnetic meansfor stabilizing the incandescent gases of the arc. The arrangementillustrated in FIG. 10 includes a bracket 136!) secured to portion [37of the base structure 12 of the lamp. A block l40b, adjustable relativeto the bracket 136b, is secured in adjusted position by bolts 1431). Inthis form, the magnetic means is inclusive of a soft iron core 156surrounded by a coil I58 having leads or conductors I60 and 161 forconnection with a current supply, preferably of low voltage.

The electromagnetic means 156, 158 is disposed in a bore in the block146b, the coil 158 being insulated from the core 156 and from the block14%. The current flow through the coil is in a direction to establishthe south or negative pole end of the core 156 to the right side of theplane A-A, shown in FIG. 6, viewed from the front of the reflector,whereby the electromagnetic forces are effective to eliminate the upwarddistortion of the body of incandescent gases providing the are asillustrated as 152 in FIG. 8 to stabilize the body of gases in morespherical form centrally between the tips of the electrodes, asillustrated at 154 in FIG. 8.

With the use of an electromagnetic means illustrated in FIG. 10, thestabilization of the body of incandescent gases may be accuratelycontrolled by varying the voltage or amperage of the current flowthrough the coil 158. The coil 158 is connected with a supply of directcurrent.

FIG. 11 is a view similar to FIG. 9 illustrating an electromagneticmeans disposed above the are produced between the electrodes and on anaxis in a transverse vertical plane passing through the gap or space 57between the electrodes. The bracket l36c carried by the member supportsa block 1400 secured to member 136a by bolts 1430. Disposed in the borein the block l40c is an electromagnetic means comprising a soft ironcore 1560 and a coil l58c surrounding the core, the coil being insulatedfrom the core 156a and from the block 1400 and provided with conductorsor leads 160C and 161C, for connection with a direct current supply.

With the electromagnetic means 156e, 158C in the position shown in FIG.11 adjacent the upper terminus of the reflector 35, the current flowthrough the coil l58c is in a direction opposite to the current flowthrough the coil 158, shown in FIG. 10. With current flow in theopposite direction, the polarity of the soft iron core 156a is reversedwhereby the electromagnetic forces act on the upwardly distortedincandescent gases of the arc to force the gases downwardly whereby theincandescent body of gases is more nearly spherical as illustrated at154 in FIG. 8 with the center of the body of gases substantially on theaxis of the electrodes.

The amperage or voltage of the current flow through the coil 158C may bevaried to vary the intensity of the magnetic forces provided by theelectromagnetic means to accurately control the position of the body ofgases of the arc between the electrodes so as to obtain maximumefficiency of projected light from the reflector 35.

The lamp housing 10 is provided with means for effectively conveyingaway the heat developed by the arc. Disposed in the housing portion 14is a blower 165 driven by a motor 166. Air is admitted to the blowerthrough an opening 168 of an annular fitting 16 mounted on the upperpanel 21 of the housing structure 14. Air entering the opening 168 isconveyed to the axial region ofthe blower 165 through a flexible tube170. The tangential outlet portion 172 of the blower is connected by aduct 174 with the hollow interior region 175 of the base structure 12.

The air from the duct 174 flows through an opening in a web 177 of thebase structure and through a duct 178 to deliver air onto the end region52 of the xenon lamp construction. The angularly disposed portion 180 ofthe base structure is fashioned with openings (not shown) to facilitateflow of air through openings 182 in the reflector support frame 32 andthrough openings 184 in the base structure to facilitate cooling ofcomponents in the rear region of the lamp housing 10. The air deliveredby the blower is vented through the stack 24 to the atmosphere.

While the most efficient stabilizing effect of the magnetic means isattained with the magnet positioned either directly below or above theregion of the arc, it is to be understood that the magnetic means may beslightly out of a vertical position through the arc and secure effectivestabilization of the body ofincandescent gases. The universal adjustingmeans for the xenon lamp 48 hereinbefore described provides an efficientand effective means for accurately positioning the arc between theelectrodes at the focal point of the reflector 35.

It will be seen that through the universal adjustment for the xenon lampand the utilization of the stabilizing forces of magnetic means forcontrolling the relative position of the body of incandescent gases atthe arc, a most efficient utilization and projection of light from thearc is attained.

Furthermore, in utilizing an are provided in a gas sealed envelope thereis no residue deposited upon the reflector surface such as isencountered in the use of an unconfined arc provided between carbonelectrodes.

It is apparent that, within the scope of the invention, modificationsand different arrangements may be made other than as herein disclosed,and the present disclosure is illustrative merely, the inventioncomprehending all variations thereof.

Iclaim:

1. In combination, a housing, a lamp in said housing comprising anelongated sealed envelope containing an inert gas and electrodes spacedto provide an are by the passage of electric current between theelectrodes, a reflector arranged to project light from the arc, lampsupporting means in the housing, said lamp supporting means includingmeans engaging the lamp adjustable lengthwise of the housing foradjusting the position of the lamp lengthwise of the axis of theelectrodes, second adjustable means operatively engaging the lamp formoving an end region of the lamp vertically and transversely of the axisof the reflector, and a permanent magnet spaced laterally of the arebetween the electrodes, the polarity of the magnet being arranged toinfluence the position of the incan descent gases at the arc to effect astabilization of the incandescent gases at the region of aresubstantially congruent with the focal point of the reflector.

2, ln combination, a housing, a lamp in said housing comprising anelongated sealed envelope containing an inert gas and electrodes spacedto provide an arc by the passage of electric current between theelectrodes, a reflector arranged to project light from the arc, lampsupporting means in the housing, said lamp supporting means includingmeans engaging the lamp adjustable lengthwise of the housing foradjusting the position of the lamp lengthwise of the axis of theelectrodes, second adjustable means operatively engaging the lamp formoving an end region of the lamp vertically and transversely of the axisof the reflector, a permanent magnet spaced laterally of the are betweenthe electrodes, the polarity of the magnet being arranged to influencethe position of the incandescent gases at the arc to effect astabilization of the incandescent gases at the region of aresubstantially congruent with the focal point of the reflector, and meanssupporting the magnet for adjusting the magnet with respect to theregion between the tips ofthe electrodes.

3. An arc lamp construction comprising, in combination. a housingincluding a base portion, an arc lamp in said housing comprising anelongated sealed envelope containing an inert gas and electrodes spacedto provide an arc by the passage of electric current between theelectrodes, at reflector, means mounting the reflector in the housing,support means for the lamp, said support means including a first member,rotatable means on the base portion supporting the first member foradjusting said member longitudinally of the housing, clamp meansengaging the envelope of the lamp, said clamp means being mounted forlimited articulation with respect to said first member, a second membermovably mounted on the base portion and engaging an end region of thelamp, first means for adjusting said second member in a directiontransversely of the housing, second means for adjusting said secondmember in a substantially vertical direction, and magnetic means spacedfrom the region of the arc for influencing the position of theincandescent gases at the region of the arc.

4. The combination according to claim 3 wherein the magnetic means is apermanent magnet, and support means for the magnet for adjusting thedistance of the magnet from the region of the arc.

5. The combination according to claim 3 including electromagnetic meansspaced from the arc for influencing the position of the incandescentgases at the region of the arc.

6. The combination according to claim 3 including a control memberaccessible exteriorly of the base portion for adjusting the relativeposition of said first member, and second and third control membersaccessible exteriorly of the base portion for manipulating said firstand second means for adjusting an end region of the lamp in verticalandhorizontal directions.

7. An arc lamp construction comprising, in combination, a

housing including a base portion, an arc lamp in said housing comprisingan elongated sealed envelope containing an inert gas and electrodesspaced to provide an arc by the passage of electric current between theelectrodes, a reflector, means mounting the reflector in the housing,means supporting the lamp in the housing with the electrodes in asubstantially horizontal position, said lamp supporting means includinga first member, rotatable means on the base portion supporting the firstmember for adjusting said member longitudinally of the housing, bracketmeans engaging the envelope of the lamp, said bracket means beingmounted for limited articulation with respect to said first member, asecond member movably mounted on the base portion and engaging an end region of the lamp, first means for adjusting said second member in adirection transversely of the housing, second means for adjusting saidsecond member in a substantially vertical direction, and magnetic meansspaced from the region of the are for influencing the position of theincandescent gases at the region of the arc.

1. In combination, a housing, a lamp in said housing comprising anelongated sealed envelope containing an inert gas and electrodes spacedto provide an arc by the passage of electric current between theelectrodes, a reflector arranged to project light from the arc, lampsupporting means in the housing, said lamp supporting means includingmeans engaging the lamp adjustable lengthwise of the housing foradjusting the position of the lamp lengthwise of the axis of theelectrodes, second adjustable means operatively engaging the lamp formoving an end region of the lamp vertically and transversely of the axisof the reflector, and a permanent magnet spaced laterally of the arcbetween the electrodes, the polarity of the magnet being arranged toinfluence the position of the incandescent gases at the arc to effect astabilization of the incandescent gases at the region of arcsubstantially congruent with the focal point of the reflector.
 2. Incombination, a housing, a lamp in said housing comprising an elongatedsealed envelope containing an inert gas and electrodes spaced to providean arc by the passage of electric current between the electrodes, areflector arranged to project light from the arc, lamp supporting meansin the housing, said lamp supporting means including means engaging thelamp adjustable lengthwise of the housing for adjusting the position ofthe lamp lengthwise of the axis of the electrodes, second adjustablemeans operatively engaging the lamp for moving an end region of the lampvertically and transversely of the axis of the reflector, a permanentmagnet spaced laterally of the arc between the electrodes, the polarityof the magnet being arranged to influence the position of theincandescent gases at the arc to effect a stabilization of theincandescent gases at the region of arc substantially congruent with thefocal point of the reflector, and means supporting the magnet foradjusting the magnet with respect to the region between the tips of theelectrodes.
 3. An arc lamp construction comprising, in combination, ahousing including a base portion, an arc lamp in said housing comprisingan elongated sealed envelope containing an inert gas and electrodesspaced to provide an arc by the passage of electric current between theelectrodes, a reflector, means mounting the reflector in the housing,support means for the lamp, said support means including a first member,rotatable means on the base portion supporting the first member foradjusting said member longitudinally of the housing, clamp meansengaging the envelope of the lamp, said clamp means being mounted forlimited articulation with respect to said first member, a second membermovably mounted on the base portion and engaging an end region of thelamp, first means for adjusting said second member in a directiontransversely of the housing, second means for adjusting said secondmember in a substantially vertical direction, and magnetic means spacedfrom the region of the arc for influencing the position of theincandescent gases at the region of the arc.
 4. The combinationaccording to claim 3 wherein the magnetic means is a permanent magnet,and support means for the magnet for adjusting the distance of themagnet from the region of the arc.
 5. The combination according to claim3 including electromagnetic means spaced from the arc for influencingthe position of the incandescent gases at the region of the arc.
 6. Thecombination according to claim 3 including a control member accessibleexteriorly of the base portion for adjusting the relative position ofsaid first member, and second and third control members accessibleexteriorly of the base portion for manipulating said first and secondmeans for adjusting an end region of the lamp in vertical and horizontaldirections.
 7. An arc lamp construction comprising, in combination, ahousing including a base portion, an arc lamp in said housing comprisingan elongated sealed envelope containing an inert gas and electrodesspaced to provide an arc by the passage of electric current between theelectrodes, a reflector, means mounting the reflector in the housing,means supporting the lamp in the housing with the electrodes in asubstantially horizontal position, said lamp supporting means includinga first member, rotatable means on the base portion supporting the firstmember for adjusting said member longitudinally of the housing, bracketmeans engaging the envelope of the lamp, said bracket means beingmounted for limited articulation with respect to said first member, asecond member movably mounted on the base portion and engaging an endregion of the lamp, first means for adjusting said second member in adirection transversely of the housing, second means for adjusting saidsecond member in a substantially vertical direction, and magnetic meansspaced from the region of the arc for influencing the position of theincandescent gases at the region of the arc.